The present invention relates to the precision machining of wax ring patterns for rings which are subsequently to be cast in precious metals by the lost wax investment casting process. Heretofore the forming of wax ring patterns was a manual process, involving the free-hand carving of the pattern by the jeweler or goldsmith and uniformity of the pattern was difficult to achieve. In a previous disclosure, now U.S. Pat. No. 4,626,145, which is fully incorporated herein by reference, I disclosed a wax ring preform sizing tool which the goldsmith could employ to size the interior of a wax ring pattern to a precise ring size with perfect concentricity with the outside of the pattern. The present invention discloses an improvement on that tool and adds indexing and machining functions which enable the goldsmith to index the tool in fixed radial positions, to file precise flat surfaces on the exterior of a wax ring preform, and to perform a variety of machining operations on the exterior of a wax ring pattern while the ring pattern is still a part of a wax ring preform tube. The tool enables the goldsmith to work on a wax ring pattern with machine shop precision with a simple hand tool.
No tools designed exclusively for working on wax ring patterns have been available to the trade before the invention of the wax ring preform sizing tool cited in the above referenced patent. The goldsmith began his operations to form a wax pattern by starting with a wax ring preform tube, a cylinder of wax having a bore size smaller than the smallest ring size. Wax ring preform tubes are supplied to the trade as cylinders from 6 to 12 inches long which may have bores which are not concentric with the exterior of the preform, e.g., cylinders with non-concentric bores or preforms having an extended flat surface. A wax ring pattern the width of the ring was cut from the preform tube and the goldsmith then proceeded to fashion a wax ring pattern by carving and shaping the the ring desired design and sizing the interior of the ring pattern to the required ring size using free hand carving and shaping techniques. The reference patent disclosed a tool which would size the interior of a wax ring pattern to the correct finger size while it was still a part of the wax ring preform. The present invention provides a pilot guided, indexable wax ring pattern machining tool which permits the goldsmith to machine the exterior of a wax ring pattern while it is still a part of the wax ring preform tube. The tool provides the goldsmith with the capability of indexing the tol in fixed radial positions, freely rotating the tool in order to perform various turning, shaping, facaeting and drilling operations on the exterior of the wax ring pattern attached to the ring preform tube.